Periodontal diseases in man are bacterial infections in which Gram negative bacteria play an essential role. During the last decade it has become clear that the subgingival microbiota associated with this disease is not uniform, but is different in the various clinical forms. The adult form of periodontitis is often characterized by an anaerobic type of microflora in which, among others, black-pigmented Bacteroides species dominate i.e. Bacteroides gingivalis and Bacteroides intermedius. On the other hand, in the local form of juvenile periodontitis, Actinobacillus actinomycetemcomitans seems to be an etiological agent.
Scientific data have become available that show that A. actinomycetemcomitans is an important etiological factor in several forms of periodontitis. There is substantive evidence that this bacterium is not only involved in localized juvenile periodontitis, but it is also associated with severe adult periodontitis. Studies have revealed that A. actinomycetemcomitans associated periodontitis is more difficult to treat with conventional mechanical therapy than other forms of periodontitis. Conventional mechanical therapy includes supra and subgingival debridement and periodontal surgery. Furthermore, it has been shown that success of treatment in A. actinomycetemcomitans positive patients is strongly associated with the eradication of this microorganism in both juveniles and adults. Since conventional mechanical therapy is not able to arrest the disease progression in most A. actinomycetemcomitans positive patients, antibiotics have been introduced as an adjunct to mechanical and surgical treatment of A. actinomycetemcomitans associated periodontitis. The antibiotic of choice is on of the tetracyclines (tetracycline, doxycycline and minocycline). Disadvantages of the use of tetracyclines relate to the fact that their biological effects are bacteriostatic and include the relatively long period of appliance (2-7 weeks) and often the recolonization of the pockets of A. actinomycetemcomitans after some time.
Therefore, there still exists a need for an effective treatment for A. actinomycetemcomitans related periodontitis.